Use tool instead of compilation runtime in jvm_import actions (#1059)

PR #1058 made the `jvm_import` actions use Java toolchains rather than
host tools, but chose the runtime used to run `javac` instead of the
runtime used to run build tools. The latter can be configured via
`--tool_java_runtime_version` while the former is fixed in the Java
compilation toolchain.

Author: fmeum

private/rules/jvm_import.bzl

@@ -23,7 +23,7 @@ def _jvm_import_impl(ctx):
         workspace_name = visible_name,
     )
 
-    java_runtime = ctx.toolchains["@bazel_tools//tools/jdk:toolchain_type"].java.java_runtime
+    java_runtime = ctx.toolchains["@bazel_tools//tools/jdk:runtime_toolchain_type"].java_runtime
     add_jar_manifest_entry_jar = ctx.file._add_jar_manifest_entry
 
     injar = ctx.files.jars[0]
@@ -118,5 +118,5 @@ jvm_import = rule(
     },
     implementation = _jvm_import_impl,
     provides = [JavaInfo],
-    toolchains = ["@bazel_tools//tools/jdk:toolchain_type"],
+    toolchains = ["@bazel_tools//tools/jdk:runtime_toolchain_type"],
 )