Meta: Use absolute paths in Meta/analyze-qemu-coverage.sh

This is a bit easier to read in the output when running locally, and a
bit better script hygiene overall.

Meta/analyze-qemu-coverage.sh

@@ -3,6 +3,7 @@
 set -eo pipefail
 
 SCRIPT_DIR="$(dirname "${0}")"
+SERENITY_ROOT="$(realpath "${SCRIPT_DIR}"/..)"
 
 if [ -z "$SERENITY_ARCH" ]; then
  SERENITY_ARCH="x86_64"
@@ -13,7 +14,7 @@ if [ "$SERENITY_TOOLCHAIN" = "Clang" ]; then
  toolchain_suffix="clang"
 fi
 
-BUILD_DIR="${SCRIPT_DIR}/../Build/${SERENITY_ARCH}${toolchain_suffix}"
+BUILD_DIR="${SERENITY_ROOT}/Build/${SERENITY_ARCH}${toolchain_suffix}"
 TEMP_PROFDATA="$BUILD_DIR/tmp_profile_data"
 
 mkdir -p "$TEMP_PROFDATA"
@@ -62,12 +63,12 @@ if [ ! -f "$COVERAGE_PREPARE" ]; then
  fi
 fi
 
-CLANG_BINDIR="${SCRIPT_DIR}/../Toolchain/Local/clang/bin"
+CLANG_BINDIR="${SERENITY_ROOT}/Toolchain/Local/clang/bin"
 
 # shellcheck disable=SC2128,SC2086 # all_binaries variable needs expanded to space separated string, not newline separated string
 python3 "$COVERAGE_PREPARE" \
  --unified-report \
- -C "$SCRIPT_DIR/.." \
+ -C "${SERENITY_ROOT}" \
  "$CLANG_BINDIR/llvm-profdata" "$CLANG_BINDIR/llvm-cov" \
  "$TEMP_PROFDATA/" \
  "$BUILD_DIR/reports/" \