i888 Use correct java compiler for JUnit tests

[johnbrvc]

Description of what the PR does

Since Eclipse 4.17 (2020-09), Java 11 (or newer) is the default JDK that ships with Eclipse. Previously, it was Java 8 (1.8). This PR attempts to track down the correct JDK to use for compiling the JUnit test programs. The JDK must match the currently running JVM in order to qualify. A search of the JAVA_HOME/bin and folders on the PATH environment variable are checked for the presence of the corresponding JDK (javac[.exe]). The code only checks for the presence of the Java version string in the folder name. It could be expanded to actually attempt to run "javac -version" in each folder, but that shouldn't be necessary, and is highly inefficient.

The reason for this PR is that the JUnits requiring compiles were using Eclipse's JDK (Version >11), but attempting to execute the produced class files using JRE 1.8. This lead to the errors described in #888.

Issue which the PR addresses

Fixed #888

Environment in which the PR was developed (OS,IDE, Java version, etc.)

Windows 11
Eclipse 2021-12, with JVM org.eclipse.justj.openjdk.hotspot.jre.full.win32.x86_64_17.0.1.v20211116-1657
JDK 1.8.0_351

Precise steps for testing the PR (i.e., how to demonstrate that it works correctly)

Run all JUnits. They should pass now. Previously, the ones in #888 (ExecuteTest, among others) did not pass.

[troy2914]

Tested with jdk17 as first in my PATH (and only java in my PATH), generated a version 61.0 PracticeA.class
added my Amazon Corretto 8 to the end my PATH /Library/Java/JavaVirtualMachines/amazon-corretto-8.jdk/Contents/Home/bin,
still generated a version 61.0 class.

[troy2914]

btw, standard location on MacOS is for the jdk to be under
/Library/Java/JavaVirtualMachines
where I have

/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_151.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_171.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_201.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk
/Library/Java/JavaVirtualMachines/jdk1.8.0_65.jdk

along with the amazon-corretto one

[johnbrvc]

Tested with jdk17 as first in my PATH (and only java in my PATH), generated a version 61.0 PracticeA.class added my Amazon Corretto 8 to the end my PATH /Library/Java/JavaVirtualMachines/amazon-corretto-8.jdk/Contents/Home/bin, still generated a version 61.0 class.

Changed so it actually runs "javac -version" on every javac or javac.exe on the JAVA_HOME/bin and PATH until it finds one that matches instead of just looking for the version in the folder string.