misc/wasm: set PATH variable in exec

The PATH variable is required to run the testenv tests.
Set it for all the runtime invocations where we don't
already set it by inheriting from the environment.

For #59583
For #59907
For #60097

Change-Id: If582dd8f086e3f40bc58d555f6034dcffe6f8e5f
Reviewed-on: https://go-review.googlesource.com/c/go/+/498616
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>

misc/wasm/go_wasip1_wasm_exec

@@ -5,13 +5,13 @@
 
 case "$GOWASIRUNTIME" in
 	"wasmedge")
-		exec wasmedge --dir=/ --env PWD="$PWD" ${GOWASIRUNTIMEARGS:-} "$1" "${@:2}"
+		exec wasmedge --dir=/ --env PWD="$PWD" --env PATH="$PATH" ${GOWASIRUNTIMEARGS:-} "$1" "${@:2}"
 		;;
 	"wasmer")
-		exec wasmer run --dir=/ --env PWD="$PWD" ${GOWASIRUNTIMEARGS:-} "$1" -- "${@:2}"
+		exec wasmer run --dir=/ --env PWD="$PWD" --env PATH="$PATH" ${GOWASIRUNTIMEARGS:-} "$1" -- "${@:2}"
 		;;
 	"wasmtime")
-		exec wasmtime run --dir=/ --env PWD="$PWD" --max-wasm-stack 1048576 ${GOWASIRUNTIMEARGS:-} "$1" -- "${@:2}"
+		exec wasmtime run --dir=/ --env PWD="$PWD" --env PATH="$PATH" --max-wasm-stack 1048576 ${GOWASIRUNTIMEARGS:-} "$1" -- "${@:2}"
 		;;
 	"wazero" | "")
 		exec wazero run -mount /:/ -env-inherit -cachedir "${TMPDIR:-/tmp}"/wazero ${GOWASIRUNTIMEARGS:-} "$1" "${@:2}"