Add common `runBlocking` for convenience

mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/internal/runBlocking.kt

+package net.mamoe.mirai.utils.internal
+
+import kotlinx.coroutines.CoroutineScope
+import kotlin.coroutines.CoroutineContext
+
+/**
+ * Mirror of `runBlocking` from `kotlinx.serialization` on JVM
+ */
+internal actual fun <T> runBlocking(
+    context: CoroutineContext,
+    block: suspend CoroutineScope.() -> T
+): T = kotlinx.coroutines.runBlocking(context, block)
\ No newline at end of file

mirai-core/src/commonMain/kotlin/net.mamoe.mirai/utils/internal/runBlocking.common.kt

+/*
+ * Copyright 2020 Mamoe Technologies and contributors.
+ *
+ * 此源代码的使用受 GNU AFFERO GENERAL PUBLIC LICENSE version 3 许可证的约束, 可以在以下链接找到该许可证.
+ * Use of this source code is governed by the GNU AGPLv3 license that can be found through the following link.
+ *
+ * https://github.com/mamoe/mirai/blob/master/LICENSE
+ */
+
+package net.mamoe.mirai.utils.internal
+
+import kotlinx.coroutines.CoroutineScope
+import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
+
+/**
+ * Mirror of `runBlocking` from `kotlinx.serialization` on JVM.
+ */
+internal expect fun <T> runBlocking(
+    context: CoroutineContext = EmptyCoroutineContext,
+    block: suspend CoroutineScope.() -> T
+): T
\ No newline at end of file

mirai-core/src/jvmMain/kotlin/net/mamoe/mirai/utils/internal/runBlocking.kt

+package net.mamoe.mirai.utils.internal
+
+import kotlinx.coroutines.CoroutineScope
+import kotlin.coroutines.CoroutineContext
+
+/**
+ * Mirror of `runBlocking` from `kotlinx.serialization` on JVM.
+ */
+internal actual fun <T> runBlocking(
+    context: CoroutineContext,
+    block: suspend CoroutineScope.() -> T
+): T = kotlinx.coroutines.runBlocking(context, block)
\ No newline at end of file