Fix bitrot: RSTest_CompatLib[19] tests stopped building

(1) Incorrect path to librsjni.so because of typo in earlier change;
    fixed by fixing typo.

(2) clang did not specify the target architecture (I don't know what
    changed so that this no longer works); fixed by specifying target
    architecture and changing from gcc linker to lld (gcc linker didn't
    understand the options it was being passed by clang).

Test: blueline-userdebug
Test: make -j FORCE_BUILD_RS_COMPAT=true ENABLE_RSTESTS=true \
        RSTestForward_21_1_2 RSTestForward_22_0_2 \
        RSTestForward_23_0_3 RSTestForward_24_0_3 RSTestForward_25_0_2 \
        RSTestBackward RSTestBackward19 RSTest RSTest_Compat RSTest_Compat19
Test: unzip -t ${PATH_TO_APK}
      # confirm that .so files are present in RSTest_Compat[19] but not
        for the other APKs
      # confirm that .bc files are present in RSTestBackward19 but not
        for the other APKs
Test: adb shell am instrument [--abi armeabi-v7a] \
        -w ${TEST_PACKAGE_NAME}/androidx.test.runner.AndroidJUnitRunner
      # Run four times:
      #   "--abi" argument present or absent; always omit for
      #     RSTest_Compat[19], which only support platform default ABI
      #   "adb shell setprop debug.rs.forcecompat 0" or "1"
      # Note that RSTestBackward19 only supports 32-bit ABI, so both
      #   runs (with and without "--abi" argument) are actually armeabi-v7a
Test: After run, check logcat for RenderScript_jni
      # (missing): not built against support library; expected for all
        tests except RSTest_Compat[19]
      # "RenderScript_jni: RS native mode"; expected for RSTest_Compat[19]
        when setprop debug.rs.forcecompat is 0
      # "RenderScript_jni: RS compat mode"; expected for RSTest_Compat[19]
        when setprop debug.rs.forcecompat is 1

Change-Id: Icfaa226f2e1bfa909cb3bcbbe960f2804c355d2a