Remove errors during first run of runpaltests.h

If you run `runpaltests.h` for first time, you will see 2 errors about file or folder not found.

First error comes from using `RELATIVE_PATH_TO_PAL_TESTS` which does not used anywhere, except maybe some platform where you can `cd` to non-existing folder. In that case 3rd parameter to script would be interpreted incorrectly. I doubt that, but who know what's somewhere deep in infra.

Second error is entirely preventable, since `cd $PAL_TEST_OUTPUT_DIR` does not affect anything until subsequent `cd $PAL_TEST_OUTPUT_DIR` on line 118.
 
Discovered here dotnet#62625 (comment)

src/coreclr/pal/tests/palsuite/runpaltests.sh

@@ -32,13 +32,6 @@ pushd $BUILD_ROOT_DIR
 
 export LD_LIBRARY_PATH=$BUILD_ROOT_DIR:$LD_LIBRARY_PATH
 
-# Create absolute path to the file that contains a list of PAL tests to execute.
-# This file is located next to this script in the source tree
-RELATIVE_PATH_TO_PAL_TESTS=$0
-# Remove the name of this script from the path
-RELATIVE_PATH_TO_PAL_TESTS=${RELATIVE_PATH_TO_PAL_TESTS%/*.*}
-# Change current directory to the location of this script
-cd $RELATIVE_PATH_TO_PAL_TESTS
 # Environment variable PWD contains absolute path to the current folder
 # so use it to create absolute path to the file with a list of tests.
 PAL_TEST_LIST=$BUILD_ROOT_DIR/paltestlist.txt
@@ -79,8 +72,6 @@ then
   fi
 fi
 
-cd $PAL_TEST_OUTPUT_DIR
-
 echo PAL tests will store their temporary files and output in $PAL_TEST_OUTPUT_DIR.
 if [ "$COPY_TO_TEST_OUTPUT_DIR" != "$PAL_TEST_OUTPUT_DIR" ]; then
   echo Output files will be copied to $COPY_TO_TEST_OUTPUT_DIR at the end.