Ensure using the given executable path. (#10525)

Ensure using the given executable path. (#10525)

* Ensure using the given executable path.

Fix the bug that corerun trying to load the executable from current directory even if the user has specified a full path of the executable.

Fix #5631

* Revert "Ensure using the given executable path."

This reverts commit d237e6329f85132429176a0644cf6d93c9437ff4.

* Partially implemented.

* Ensure app context using correct IL file path.

Extracting simple name from the given file path and look up its value in tpa list. If the value does not equal to the given file path, we update the value with correct given file path.

Fix #5631

* Re-arrange the slashIndex to eliminate unneccessary code.

* A few performance improvement with a memory leak bug fixed.

* Added the absolute path of target assembly to tpa list.

Fix #5631

* Added the path of target assembly to tpa on Windows.

Fix #5631