Report error on circular local dependencies (#731)

If a stack overflow is found during project evaluation, present any
circular imports found in the dependency graph.

pkl-core/src/test/resources/org/pkl/core/project/projectCycle1/PklProject

@@ -0,0 +1,12 @@
+amends "pkl:Project"
+
+package {
+  name = "projectCycle1"
+  version = "1.0.0"
+  packageZipUrl = "https://bogus.value"
+  baseUri = "package://localhost:0/projectCycle1"
+}
+
+dependencies {
+  ["projectCycle2"] = import("../projectCycle2/PklProject")
+}

pkl-core/src/test/resources/org/pkl/core/project/projectCycle2/PklProject

@@ -0,0 +1,12 @@
+amends "pkl:Project"
+
+package {
+  name = "projectCycle2"
+  version = "1.0.0"
+  packageZipUrl = "https://bogus.value"
+  baseUri = "package://localhost:0/projectCycle2"
+}
+
+dependencies {
+  ["projectCycle3"] = import("../projectCycle3/PklProject")
+}

pkl-core/src/test/resources/org/pkl/core/project/projectCycle3/PklProject

@@ -0,0 +1,12 @@
+amends "pkl:Project"
+
+package {
+  name = "projectCycle3"
+  version = "1.0.0"
+  packageZipUrl = "https://bogus.value"
+  baseUri = "package://localhost:0/projectCycle3"
+}
+
+dependencies {
+  ["projectCycle2"] = import("../projectCycle2/PklProject")
+}

pkl-core/src/test/resources/org/pkl/core/project/projectCycle4/PklProject

@@ -0,0 +1,7 @@
+amends "pkl:Project"
+
+import "PklProject"
+
+dependencies {
+  ["projectCycle1"] = import("../projectCycle1/PklProject")
+}