[WASM] Initial infrastructure

- New module ":compiler:backend.wasm"
    - Initial compiler infra (driver, phaser, context)
    - Subset of Wasm AST
    - Skeleton of IR -> Wasm AST
    - Wasm AST -> WAT transformer

- Testing infra

- SpiderMonkey jsshell tool

compiler/ir/backend.wasm/build.gradle.kts

@@ -0,0 +1,26 @@
+plugins {
+    kotlin("jvm")
+    id("jps-compatible")
+}
+
+dependencies {
+    compile(project(":compiler:util"))
+    compile(project(":compiler:frontend"))
+    compile(project(":compiler:backend-common"))
+    compile(project(":compiler:ir.tree"))
+    compile(project(":compiler:ir.psi2ir"))
+    compile(project(":compiler:ir.backend.common"))
+    compile(project(":compiler:ir.serialization.common"))
+    compile(project(":compiler:ir.serialization.js"))
+    compile(project(":js:js.ast"))
+    compile(project(":js:js.frontend"))
+    compile(project(":compiler:backend.js"))
+
+    compileOnly(intellijCoreDep()) { includeJars("intellij-core") }
+}
+
+sourceSets {
+    "main" { projectDefault() }
+    "test" {}
+}
+