Add extra variables to erlang_vars rules

Also define a map used to conveniently pass those vars to sh_test
rules

tools/erlang_vars.bzl

@@ -1,14 +1,32 @@
+ERLANG_VARS_ENV_MAP = {
+    "OTP_VERSION": "$(OTP_VERSION)",
+    "OTP_VERSION_FILE_PATH": "$(OTP_VERSION_FILE_PATH)",
+    "OTP_VERSION_FILE_SHORT_PATH": "$(OTP_VERSION_FILE_SHORT_PATH)",
+    "ERLANG_HOME": "$(ERLANG_HOME)",
+}
+
+ERLANG_VARS_ENV_MAP_INTERNAL = ERLANG_VARS_ENV_MAP | {
+    "OTP_INSTALL_PATH": "$(OTP_INSTALL_PATH)",
+    "ERLANG_RELEASE_TAR_PATH": "$(ERLANG_RELEASE_TAR_PATH)",
+    "ERLANG_RELEASE_TAR_SHORT_PATH": "$(ERLANG_RELEASE_TAR_SHORT_PATH)",
+}
+
 def _impl(ctx):
     otpinfo = ctx.toolchains["//tools:toolchain_type"].otpinfo
     vars = {
         "OTP_VERSION": otpinfo.version,
+        "OTP_VERSION_FILE_PATH": otpinfo.version_file.path,
+        "OTP_VERSION_FILE_SHORT_PATH": otpinfo.version_file.short_path,
         "ERLANG_HOME": otpinfo.erlang_home,
     }
     if otpinfo.release_dir_tar != None:
+        vars["OTP_INSTALL_PATH"] = otpinfo.install_path
         vars["ERLANG_RELEASE_TAR_PATH"] = otpinfo.release_dir_tar.path
         vars["ERLANG_RELEASE_TAR_SHORT_PATH"] = otpinfo.release_dir_tar.short_path
 
-    return [platform_common.TemplateVariableInfo(vars)]
+    return [
+        platform_common.TemplateVariableInfo(vars),
+    ]
 
 erlang_vars = rule(
     implementation = _impl,